Friction coefficient measurement of an in vivo murine cornea

Ocular tear film mucins and lipids promote lubricity of the corneal surface during ocular movements. The mechanisms of this lubricity are difficult to model and to measure due to the delicate nature of the film itself and the conditions under which it exists. This study describes a kinetic friction coefficient measured between a glass probe and a living mouse eye. A portable custom micro-tribometer was used to prescribe sliding motions and record normal and frictional forces. Friction coefficient measured over both sliding directions resulted in μ = 0.068 under a pressure of approximately 12 kPa. In vivo measurements may enhance the understanding of corneal friction response, as well as provide an empirical friction coefficient for more complex mechanical models.